Background: The existing clinical subtype classification of basal cell carcinoma (BCC) does not adequately reflect tumor invasiveness or its relationship with histologic patterns. Objective: To suggest the upgrading classification of clinical subtype of BCC and evaluate its correlation with histologic subtypes and tumor invasiveness. Methods: This study enrolled 422 patients with 425 biopsy-proven BCC lesions. All of the patients were treated by Mohs micrographic surgery (MMS) at our hospital from January 2018 to October 2021. All BCCs were categorized according to upgrading clinical subtype classification we suggest: Basic subtypes (including nodular [N], papular [P], superficial-elevated [SE]/-flat [SF]/-depressed [SD] and infiltrative [I] subtype) and combined subtype. We conducted a retrospective study through medical record, clinical photographs, pathologic slide and MMS sheets. Results: The most common in basic subtypes was SE (23.1%), followed by N (22.1%) and I (12.0%) subtype. Nodulo-infiltrative (N-I) (8.7%) was the most common in combined subtype.In N, P, SE and SF subtype (non-aggressive group), the rate of tumor with pigmentation (63.1%) was high, non-aggressive pattern (91.4%) in histologic subtype was observed much more. In SD, I and combined subtype (aggressive group), pigmentation (24.0%) was relatively rare, aggressive and mixed pattern (74.4%) in histologic subtype was observed more. More wider surgical margin and more MMS stage number were required in aggressive group than non-aggressive group. Conclusion The upgrading classification of BCC clinical subtype can be not only described briefly and concretely for clinical appearance of BCCs but also highly correlated with histologic subtypes and tumor invasiveness.

Darier’s disease is characterized by greasy and scaly papules that primarily affect seborrheic and intertriginous areas which is caused by a mutation in the ATP2A2 gene. Histopathologically, the disease is characterized by acantholysis and dyskeratosis. Among the diverse presentations, the segmental type follows a linear distribution along the lines of Blaschko. Herein, we present a case of a 54-year-old male with generalized erythematous papules that had been linearly distributed across his body for two decades. Lesions on his trunk and extremities were confined to the right side, whereas those on the scalp and face exhibited multiple segmental presentations. Histopathological examination revealed acantholysis and dyskeratosis in the epidermis, confirming the diagnosis of type 1 segmental Darier’s disease. This case underscores the rarity of type 1 segmental Darier’s disease, particularly with multiple segmental involvement and highlights the complexity and variability of this dermatological condition.

Lichen amyloidosis is characterized by coalescent hyperpigmented papules with a predilection for the extremities and is accompanied by severe chronic pruritus. Various therapies have been attempted; however, there is no uniformly recognized effective treatment. In the first case, a 60-year-old man with a 37-year history of intractable itching presented with hyperkeratotic brown papules and coalescing plaques on the trunk and extensor surfaces of the extremities. The second case involved a 31-year-old man who presented with brownish macules and papules with a rippled pattern on the upper back and lower extremities. Histological examination of the lesions from both patients revealed epidermal hyperplasia and amorphous material deposited in the papillary dermis, which tested positive on Congo red staining. Although both patients were diagnosed with lichen amyloidosis, several treatment modalities showed limited efficacy. Subsequently, dupilumab, a treatment for severe pruritus, was administered to both patients, resulting in significant improvements.

A 34-year-old male with acne was presented with a 1-year history of multiple tiny subcutaneous nodules on his face, particularly on both cheeks. Physical examination revealed asymptomatic, palpable, and hard nodules with an acne scar. The skin lesions were more obvious when the cheeks were inflated. A skin biopsy revealed multiple focal bony trabeculae with osteoblasts in the dermis. A diagnosis of multiple miliary osteomas cutis was done. Multiple miliary osteoma cutis is a rare benign extraskeletal ossification that is considered relatively common and under-reported because of its asymptomatic behavior. Osteoma cutis is generally observed in middle-aged females with a history of acne. Male involvement rarely occurs, especially at a young age, as observed in this patient. Topical retinoids were prescribed, but the lesions did not abate at 3 months follow-up.

Traumatic tattoos are abnormal pigmentations caused by embedded foreign particles due to various injuries, including explosions, abrasions, or traffic accidents. Traumatic tattoos caused by pencils are common and considered trivial because they are usually confined to the injured site without any complications. A 4-year-old girl presented with a 5-month history of a grey-to-bluish patch on her left cheek. Histopathological examination revealed many pigment granules surrounding the blood vessels and appendages diffused from the mid to the lower dermis. Various staining methods were employed to verify that colorants caused the tattoo. To our knowledge, there have been no reports of traumatic tattoos caused by colored pencils that spread rapidly beyond the injured areas. In particular, various unexpected traumas can occur frequently in children; therefore, an accurate diagnosis is essential by differentiating it from other acquired pigmentary disorders

Darier’s disease is characterized by greasy and scaly papules that primarily affect seborrheic and intertriginous areas which is caused by a mutation in the ATP2A2 gene. Histopathologically, the disease is characterized by acantholysis and dyskeratosis. Among the diverse presentations, the segmental type follows a linear distribution along the lines of Blaschko. Herein, we present a case of a 54-year-old male with generalized erythematous papules that had been linearly distributed across his body for two decades. Lesions on his trunk and extremities were confined to the right side, whereas those on the scalp and face exhibited multiple segmental presentations. Histopathological examination revealed acantholysis and dyskeratosis in the epidermis, confirming the diagnosis of type 1 segmental Darier’s disease. This case underscores the rarity of type 1 segmental Darier’s disease, particularly with multiple segmental involvement and highlights the complexity and variability of this dermatological condition.

Lichen amyloidosis is characterized by coalescent hyperpigmented papules with a predilection for the extremities and is accompanied by severe chronic pruritus. Various therapies have been attempted; however, there is no uniformly recognized effective treatment. In the first case, a 60-year-old man with a 37-year history of intractable itching presented with hyperkeratotic brown papules and coalescing plaques on the trunk and extensor surfaces of the extremities. The second case involved a 31-year-old man who presented with brownish macules and papules with a rippled pattern on the upper back and lower extremities. Histological examination of the lesions from both patients revealed epidermal hyperplasia and amorphous material deposited in the papillary dermis, which tested positive on Congo red staining. Although both patients were diagnosed with lichen amyloidosis, several treatment modalities showed limited efficacy. Subsequently, dupilumab, a treatment for severe pruritus, was administered to both patients, resulting in significant improvements.